Most students would say there is no drug scene at Seattle Pacific. Many go their entire educational careers without ever running across drugs; this is because users are not flamboyant about their illegal habits, and most students are too square to recognize what's going on in the first place. The most common drug of choice is marijuana, naturally. Harder drugs are less common and rarely discussed openly.
Because SPU is a mostly conservative community (or at least by appearances it is), drug use is going to be carefully hidden and managed. Unless you're using them, drugs really won't be a problem or a danger on campus. That being said, if you are a drug user, it may take a while to find others like yourself, but chances are you'll have a keener eye to spot them.